NEW YORK - Democratic presidential nominee Hillary Clinton has regained a firm lead over her Republican rival Donald Trump in the run-up to November elections, polls show.

According to a CBS News poll on Monday, Mrs Clinton leads Trump by six percent, having 46 percent of support compared to 39 percent Trump secured.

Meanwhile, a CNN-ORC poll released later on the same day shows that the former secretary of state is ahead of the billionaire businessman by nine points, with the two receiving 52 and 43 percent respectively.

Similar polls conducted by the CBS and CNN-ORC after the Republican convention but before the Democratic one indicated Trump’s lead over Clinton.

According to the CBS previous poll, Trump got a two-point rise and according to the CNN-ORC poll Trump led Clinton 48-45.

Now, the CNN poll shows Clinton is also ahead of Trump in terms of policies that could move the country in the right direction, rising from 43 percent of respondents before either convention to 48 percent today.

"I think both parties got what they wanted out of their conventions," Republican National Committee chairman Reince Priebus told CNN after the network's poll was released.

The increase in the numbers came two days after Clinton formally accepted the Democratic Party’s nomination for the November election at the Democratic National Convention in Philadelphia.

The CBS survey, however, shows that Americans' negative view of Clinton still remains, even though it has eased somewhat since the convention last week.

Fifty percent think negatively of Clinton compared to 36 percent who view her positively, the poll said, adding that positive number has increased by five points and the negative one decreased by six points.

The poll also shows that thirty-one percent have a positive opinion of Trump, which is almost the same as before the Republican convention and 52 percent think of him negatively.

Another poll by the Reuters/Ipsos on Sunday showed that nearly 41 percent of likely voters said they favoured Clinton, while 35 percent expressed support for Trump.

Despite all these polls, a Gallup poll released earlier last month found that Trump and Clinton are among the worst-rated presidential candidates of the last 70 years.