More than 3.2 million patients were awaiting treatment on the NHS, according to the latest figures for June.
The statistics, which come just days after Health Secretary Jeremy Hunt announced a £250 million drive to eliminate "unacceptable" 12-month waits, show 521 people had been waiting for more than a year to start treatment.
By the end of June 93.8% of patients were enduring waits of up to 18 weeks, the figures from NHS England show.
They confirm the findings of an influential think tank which last month showed the number of people waiting was at its highest level in six years.
The King's Fund said in its report that "cracks are beginning to appear" in performance as a result of the growing financial pressures.
On Monday Mr Hunt admitted that the NHS will miss its 18-week waiting-time targets over the coming months due to a focus on treating patients whose conditions are often more complex and time-consuming, but he claimed the target will be met again by the start of 2015.
Responding to the latest figures a Department of Health spokesman said the number of people waiting more than 18 weeks to be treated is still lower than 2010 when the current Government came to power, and added that 850,000 more operations had been carried out since then.
" We know parts of the NHS are under pressure - that's why we've given the NHS support to do 100,000 extra operations this summer," said the spokesman.
"By prioritising those who have waited the longest the NHS is likely to miss the target for a while but we expect it to get back on track later in the year."
Shadow health secretary Andy Burnham accused David Cameron of failing in his pledge to cut waiting times.
"Under his Government, there are more people on NHS waiting lists and those patients are waiting longer for treatment," he said.
"In June, the NHS missed its waiting time target with 32,500 people who waited longer than 18 weeks - the highest in six years.
"Under David Cameron, people are seeing a return to that old Tory choice of suffering in silence or paying to go private."
NHS England said five Trusts had submitted either partial data or none at all for June, and Mr Burnham said it was "worrying" that full figures were not available.
"What people will find worrying about these figures is the admission for the first time that there are around 160,000 people waiting who are missing from official figures," he said.
"People need to have a clear explanation as to why official figures have underestimated waiting lists and an assurance that this will immediately be put right."
The news comes as health officials announced that a number of charities are being given funding to help the NHS in the busy winter months.
The British Red Cross is among a number of charities being called in to help with people who are most at risk of being admitted to hospital and those who need extra help when they are discharged.
NHS England is to dish out £2 million to groups, including Age UK and Royal Voluntary Service, to run projects in seven different areas of England.