Members of Parliament have voted to give themselves £10,000 each a year to spend on things like websites to boost "public understanding" of Parliament.
MPs can use the allowance for parliamentary work only
The new allowance comes on top of the £20,000 office running costs allowance and £7,000 for pre-paid envelopes.
The money cannot be spent on websites featuring party political "propaganda", with Jack Straw acknowledging some MPs might need to have a second site.
One Labour MP predicted the sites would be used for "shameless self-promotion".
Despite that warning from Tony Wright, MPs voted by a majority of 95 in favour of the government-backed motion.
'Health of democracy'
Commons Leader Jack Straw told MPs: "The purpose of this allowance is to contribute to better public understanding of what this Parliament is about and what it does...
"It's important for the health of our democracy for the public to know more about what we do."
He added it was better "not to become a propaganda tool for the use of incumbents" and it was time to "make clear what the rules are".
Previously, websites had been set up by MPs of all parties which were "not in accordance with the current rules" on how expenses can be spent.
He said material on many of the sites was found to be party political in a way that would not have been allowed if the material had been on leaflets or posters.
Mr Straw said websites funded by the extra £10,000 must not promote a party or politician, or raise funds, and must carry a message saying they are publicly paid for.
They would also have to close down while Parliament is dissolved for an election, so as not to give incumbent MPs an advantage, he added.
But Mr Wright, MP for Cannock Chase, said: "It's going to be an exercise in shameless self-promotion. It's going to tell people how wonderful we are and is paid for by our constituents."
Shadow Commons leader Theresa May said: "We owe it to our constituents to spend their taxes wisely."
She added: "I think there's a reason for changing the rules, but not for introducing a new allowance, which would enhance the position of incumbents."
Liberal Democrat spokesman David Heath said: "We have to be extremely careful when we are seen by those outside to be awarding ourselves yet another allowance of substantial size, without a clear indication of how the money spent is to the advantage of our constituents rather than us."
The existing allowance can be used for constituency news letters, press releases, petitions, contact cards and online surgeries.
It cannot be used for fundraising, campaigning, business activities, encouraging people to join a political party, or for petitions or surveys associated with national or local elections.
The £10,000 limit for the new allowance was set by the Members Estimate Committee after MPs agreed there should be money "to assist in the work of communication with the public on parliamentary business".
The committee said MPs had been told they needed to do more to communicate with the public, and that "the traditional method of communicating by letter has shown no sign of abating".
It estimated that the total annual cost of the communications allowance would be about £6m, while the pre-paid envelope allowance would be limited to £4m.
Last year, House of Commons figures showed that MPs claimed almost £86.8m in expenses and allowances - an increase of nearly £6m on the previous year.
The 2005/06 payments - about £131,000 per MP - come on top of a basic salary of about £60,000 and a pension.