dollar index, which measures the dollar's performance against a basket of six major global currencies, rose to 79.649 in Tokyo afternoon trading from 79.543 late in North America on Friday.
The premium for the forward dollar declined further on sustained receipts by exporters. The benchmark six-month forward dollar premium payable in May moved down to 160-162 paise from last Friday's close of 164-165 paise.
Far-forward contracts maturing in November also ended lower at 304-1/2-306-1/2 paise from 309-1/2-311-1/2 paise. The RBI has fixed the reference rate for the US dollar at 54.6290 and for euro at 71.8595.
The rupee remained weak against the pound sterling to 88.86 from last close of 87.82 and also dropped further against the euro to 72.16 from 71.35.
It, however, reacted downwards against the Japanese yen to end at 65.53 per 100 yen from previous close of 65.04.