The survey puts the average number of people who read the London Lite each day at 745,000, compared with 713,000 for thelondonpaper, during the six months to June this year.
These results are the first NRS readership estimates released for the afternoon freesheets, which launched head-to-head a year ago.
Having the bigger readership is a boost for London Lite, which has been trailing thelondonpaper in its circulation figures since both papers launched.
Steve Auckland, managing director of free newspapers at Associated Newspapers, said: "We are very pleased with the NRS readership estimates and profile data. This is the most accurate data available to date, and London Lite came out on top on the key measures.
"We have always maintained that a distribution figure of 400,000 is a responsible, realistic reflection of the demand for the product between 4.30 and 7.30pm. This is a great result for everyone involved with London Lite and especially editor, Ted Young, and his hard-working team.
"This information further demonstrates that we are producing the better paper. We would like to thank the agencies for supporting us for the last year without any NRS data to support their decisions."
A spokesperson for thelondonpaper said it has concerns regarding the validity of the NRS headline figure.
She said: "To compile this data, the NRS surveyed only 231 readers of thelondonpaper. During this period, more than 60m copies of thelondonpaper were distributed.
"Media buyers will understand that the NRS figures are based on a claimed readership and are subject to wide variation when confidence limits are applied. As stated on the NRS report itself, this means they are 95% confident and that the "actual" readership could be plus or minus 112,000 readers in relation to the estimate published."
Alan Brydon, head of press communication at Media Planning Group, said: "Given what we know about NRS methodology, there's always a chance that the figures may not reflect reality, but there's a bigger probability that they do, and in that case, it's rather worrying for NI. Because whether or not they are technically correct, they are the figures planners and buyers will use.
"The actual readers per copy figure is around 30% higher, suggesting greater retention and pass-on readership. Given the similarity of distribution, if this is correct then it can only be down to the appeal of the product or the fact that not all copies of thelondonpaper are distributed correctly. But personally, I find it difficult to see that much difference."According to last month's ABC figures, thelondonpaper's circulation edged up 0.82% to 500,563, while London Lite increased by 3.12% to 400,571.
The NRS was due to release the first readership figures for the freesheets back in July, covering the period from December to May. However, it delayed the release because the data from self-completed surveys could not be included until June, making its survey sample size insufficient.
The NRS estimate of the readership of Associated Newspapers' Evening Standard was 691,000 during January to June this year, down 13% from 794,000 in the same period in 2006.