The planning commission and the home ministry are locked in a hard tussle over the unique identification number project and both of them have taken the issue to prime minister Manmohan Singh for a solution.

Home minister P Chidambaram is understood to have written a letter to the prime minister asking him to instruct the planning commission to bring a note to the cabinet for an early decision on the issue.

At the centre of the controversy is the collection of bio-metric data of all residents. While the home ministry has maintained that the Registrar General of India under it has been mandated to collect the data through the National Population Register, the Nandan Nilekani-led UIDAI has also been authorised to gather the information.

The UIDAI has already collected information about 170 million people and wants extension of its mandate to cover the entire nation.

But Chidambaram has sought clarity on the status on who will capture bio-metric data -- RGI or UIDAI. The home ministry feels the data collected by UIDAI was not secure as it is not verified by a government servant.

The data collection by UIDAI has been done by hired organisations which is a cause of concern for Home minister.

However, planning commission deputy chairman Montek Singh Ahluwalia today threw his full weight behind the UIDAI saying the project should continue.

"In our view, it should continue. This can be done, parallel with whatever others (home ministry) are doing. Whatever UIDAI is doing is the right thing to do and it should be continued", he said.

When asked whether proposal would be discussed next week, Ahluwalia said, "I hope so. We have sent a cabinet note."

It may come up before the cabinet on Wednesday, sources said.

Ahluwalia said, "we have no problems if the home ministry wants to do it differently....we are not talking about national security. We are only talking about UID."

According to the home ministry proposal, chip-based smart card will be issued to all residents on the basis of record maintained by the NPR.

On concerns over duplication of work and extra burden on exchequer, he had stated that the project is well worth it.

UIDAI was mandated to issue 200 million Aadhaar numbers or national identity cards to residents by the end of this fiscal.

The commission wants more resources for the authority for continuation of its work.