Hetherington is hopeful the prospect of Rhinos' "best-ever squad", plus a price freeze and easy-payment offers will boost sales before the cost goes up on Saturday.
"We are ahead of where we were at the corresponding time last year, but behind our target," Hetherington said of sales so far.
"The news is a bit mixed. We have got through the 8,000 barrier, which is about five per cent up on where we were last year at this time.
"But we recognise we have still got quite a bit to do and one thing we are hoping is that our current members will encourage friends and relatives to also become members.
"There is a part to be played by everybody, particularly as we get up towards Christmas.
"Membership of the Rhinos will make an ideal Christmas present, particularly for youngsters."
Hetherington said the club have done everything possible to make season ticket packages affordable and attractive to fans.
"Prices have been frozen again and we have extended the early bird deadline - to buy memberships at a discounted rate - until this Friday," he pointed out.
"We aren't as elated as we hoped to be at this time, but we do understand people's economic circumstances, which is why we have introduced a £50 deposit.
"That secures a season ticket and the balance can be paid up to February 1, or we have also introduced an option to spread the cost over eight months from January.
"We have had some good feedback on that and it has proved to be very popular, but there may be people who are not aware of that.
"By freezing prices and creating an easy payment scheme, we are hoping for a pre-Christmas rush."
"We are looking forward to the new season with a lot of optimism and I think the new signings - Joel Moon and Mitch Achurch - and the emergence of Stevie Ward makes the 2013 Rhinos squad the best ever.
"It is certainly the most exciting and talented we have had and the balance throughout the squad is very good.
"We've got a group of genuinely world class players, coupled with the best young talent the club has had for many years.
"It's not just emerging talent. People like Zak Hardaker, Kallum Watkins and Stevie Ward have played in major finals at the age of 21 and - in Stevie's case - 18.
"It is a very young and exciting back line and it bears comparison with the 1960s and 70s, when Leeds had players like Alan Smith, Syd Hynes, Les Dyl and John Atkinson playing for them.
"Without getting ahead of ourselves, we can go into the new season optimistic and with a lot to look forward to."
To find out more about 2013 season tickets visit www.therhinos.co.uk/seasontickets