The satellite was originally scheduled for launch in December this year.
"SAARC satellite will be launched in March," he told reporters on the sidelines of a function in Thiruvananthapuram.
Modi, during the SAARC summit in Nepal in November 2014, had announced launching of a SAARC satellite as a gift for the benefit of members of the regional grouping in various fields, including telecommunication and tele-medicine.
Since Pakistan has 'opted out' of the project, it is now being called South Asian satellite.
India had held deliberations with experts from other SAARC countries to finalise modalities for the satellite exclusively for the regional grouping.
On GSLV Mark III likely to be launched in December, the ISRO Chairman said preparations were on in "full swing".
"We have started the assembly for the launch in Sriharikota. So we are working towards making it happen as early as possible and are targeting for launch by December end."
The rocket programme is crucial for ISRO as it would help the country launch satellites weighing around four tonnes.
To a question about plans to improve manpower and infrastructure facilities, he said. "We need to do more work means we need to have more hands.
On the third launch pad, the ISRO chief said it was necessary to make sure that the existing facility was being fully utilised.
Earlier, he addressed around 1,000 sportspersons drawn from 14 ISRO centres who are participating in the inter-centre sports meet, saying such activities helped to break barriers and reinvigorate mentally and physically, besides improving team work.
Vikram Sarabhai Space Centre Director Dr K Sivan was also present.
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