Free-to-use cash machines, banks on wheels and the use of local Post Office branches could all be solutions.
The move expands a former voluntary agreement to assist vulnerable customers when towns and villages become bank-free.
But there will be no punishment if banks fail to provide alternatives.
Banks, the government and consumer groups have signed up to the new protocol, which will be reviewed independently in a year.
Business Secretary Vince Cable said that banks had a duty to ensure that vulnerable customers, small businesses and those in rural communities should have access to counter services to conduct their financial affairs.
However, many residents of towns and villages have found that they have to travel to the nearest major conurbation in order to get to a bank branch.
Banks should now consider the proximity of alternative branches before a closure - although proximity can be very different, depending on the mobility of customers, ranging from young car drivers to older people reliant on public transport. The age profile of the branch's customers will be part of the review.
Individual banking institutions should come to arrangements with the Post Office to allow counter services for current account customers, the government has said.
A system that allows customers to compare the suitability of current accounts from different banks is also being unveiled.
Comparison website Gocompare.com will run a government-backed system that allows customers of five banks to download their last 12 months of statements to judge whether they could get a better deal elsewhere.
"The initiative will allow people to compare accounts based on their needs and could help them save money if they switch," said Richard Lloyd, executive director at consumer group Which?.
"However, it will only be a success if the banks play their part in making people aware of the service and the benefits of switching, and if it is rolled out across all current account providers."
Initially, it will only be available to customers of Barclays, HSBC, Lloyds, RBS and Santander.
Only 6% of current account customers switched provider in 2014, despite the system becoming quicker and easier.

McKinnon was also interviewed for the vacancy at St Mirren, but the Paisley club instead appointed Dumbarton's Ian Murray.
The 44-year-old has joined Rovers on a two-year contract.
Chief executive Eric Drysdale said: "Ray ticks all the boxes and we are confident he can take us forward."
Rovers were seeking a new manager after Grant Murray, who had been in charge for three years, was sacked in April following five straight defeats.
Now Malpas, the 52-year-old former Motherwell and Swindon Town manager who had been in his role since December, has also left the Kirkcaldy club.
"As promised, the board has taken great care in its search for someone to replace Grant Murray," said Drysdale.
"We spoke in detail to four of the very best candidates from a very long list of applicants.
"Only one, Ray, was formally offered the job and we are very pleased that he has accepted."
Former Rovers player McKinnon, who previously managed junior club Lochee United, recently signed a new contract at Glebe Park.
First-team coach Laurie Ellis took charge of the Kirkcaldy side for the final Scottish Championship match of the season - a 2-2 draw away to Dumbarton - as they finished in sixth place.
McKinnon, who took over as Brechin boss in 2012, led his side to a fourth-place finish in League One this season.
However, they missed out on promotion after losing 2-1 on aggregate to Alloa Athletic in their play-off semi-final.
McKinnon, who began his career at Tannadice, had two spells as a player at Stark's Park.
He made five appearances in 2000 after leaving Livingston before joining Portadown, and Rovers were his final senior club, making 12 appearances in 2003 after leaving Montrose.
McKinnon also had spells with Nottingham Forest, Luton Town, Stirling Albion, East Fife and Torquay United and finished his career in junior football with Lochee and Broughty Athletic.
Banks must investigate alternative arrangements for customers before closing the last bank in town, under a new agreement.
[NEXT_CONCEPT]
Ray McKinnon has left Brechin City to become Raith Rovers manager, with Maurice Malpas standing down as director of football at Stark's Park.