Chief medical officer for England Sir Liam Donaldson said the data suggested an upturn was on the way.
Experts have been predicting a second wave of swine flu will hit the UK in the winter months following a lull over the summer break.
Scotland has also seen a rise in the number of cases in the last week.
Sir Liam said: ''There has been a slight upturn this week. We don't know whether it will be sustained but I think it's one of the few straws in the wind that we might be seeing an upturn.''
There are now 143 people in hospital in England, of whom 23 are in intensive care.
The total number of deaths linked to the virus has risen by one in the last week to 67 in England.
Sir Liam said the figures "begin to suggest swine flu is coming back".
"We would naturally have hoped for a bit more breathing space before it started again."
A deal has been struck with GPs in the UK, who will receive £5.25 for each dose of the swine flu vaccine they give to patients. It is hoped that at-risk groups, such as those with diabetes or asthma, will be able to get their normal seasonal flu jab at the same time.
However, GPs are being told not to hold off starting the seasonal flu vaccine programme until the swine flu vaccine arrives.
The first doses of swine flu vaccine are expected to be given in October.
There have been nine deaths in Scotland, two in Northern Ireland and one in Wales. More than 1.3 million people have been assessed via the National Pandemic Flu Service for England, with 522,890 collections of anti-viral drugs.
The Government is now waiting for European regulators to license the swine flu vaccine before giving it to health workers and at-risk groups across the UK.
Sir Liam said that it was hoped the vaccine could be given to people "as quickly as possible" after it receives its licence.
Tests on GlaxoSmithKline's flu vaccine has shown that a good immune response can be achieved with just one dose rather than two.
However, Sir Liam said the under-13s and over-65s may need two doses, although research was ongoing. Sir Liam also said there had been suspected outbreaks of swine flu in six English schools, all of which had higher than normal absence rates.
Two schools are in South Yorkshire, one in Carlisle, one in the North East and two in London.
Sir Liam said there were no plans to close schools as the virus was circulating in the community, meaning such efforts would have little value. There have been 25 worldwide cases of resistance to Tamiflu to date, including one new confirmed case and another suspected case in the UK.
However, Sir Liam said these were of no public health significance at the moment.
In Scotland, Health Secretary Nicola Sturgeon said there had been a significant rise in the number of suspected cases. Officials said about 6,180 people have caught H1N1 in the past week.
The rate of GP consultations for flu-like illnesses - not necessarily H1N1 - was 53.3 per 100,000 people, an increase from last week's figure of 43.9.
Around the world, the number of new cases is decreasing in Australia, New Zealand, South Africa, Chile and Argentina, and is rising in the USA and Eastern Europe. In central and Western Europe, figures remain low or at a moderate level.